Simplify the expression. $(5a+4)(5a-8)$
Explanation: First distribute the ${5a+4}$ onto the ${5a}$ and ${-8}$ $ = {5a}({5a+4}) + {-8}({5a+4})$ Then distribute the ${5a}.$ $ = ({5a} \times {5a}) + ({5a} \times {4}) + {-8}({5a+4})$ $ = 25a^{2} + 20a + {-8}({5a+4})$ Then distribute the ${-8}$ $ = 25a^{2} + 20a + ({-8} \times {5a}) + ({-8} \times {4})$ $ = 25a^{2} + 20a - 40a - 32$ Finally, combine the $x$ terms. $ = 25a^{2} - 20a - 32$